Cannot setup Hummingbird Minification

The initial question was why all the files in minification have the "Pending" status and that doesn't change for hours while on other sites it lasts no more than a couple of minutes.

After putting CDN into "Dev" mode (to bypass it) and purging cache, I can't even enable minification again. The server is using Nginx + Redis cache and I suppose that cache is related but I might be missing something. Unfortunately, this cache cannot be disabled. Is there any solution for this?